Since the nineteenth century, the development of international humanitarian law has been marked by complex entanglements of legal theory, historical trauma, criminal prosecution, historiography, and politics. All of these factors have played a role in changing views on the applicability of international law and human-rights ideas to state-organized violence, which in turn have been largely driven by transnational responses to German state crimes. Here, Annette Weinke gives a groundbreaking long-term history of the political, legal and academic debates concerning German state and mass violence in the First World War, during the National Socialist era and the Holocaust, and under the GDR.